Baby teeth and autism: UNC part of large NIH study of environmental risk factors

Autism researchers will use new technology to study baby teeth of children who have siblings with autism to learn if siblings are more likely to develop the disorder if exposed to chemicals while in the womb.

CHAPEL HILL, NC – As part of the new $157 million NIH ECHO initiative, a research network led by UNC’s Joseph Piven, MD, director of the Carolina Institute for Developmental Disabilities, will join researchers across the country in a study to explore what baby teeth can tell us about a child’s risk of developing autism if the child was exposed to chemicals in the womb.

Drexel University’s Craig Newschaffer, PhD, is the principal investigator. To conduct the study, his team will work with the NIH Autism Center of Excellence directed by Piven, the Thomas E. Castelloe Distinguished Professor of Psychiatry in the UNC School of Medicine.

“This study will allow us to examine the impact of exposure to environmental toxins at various times during a mother’s pregnancy on the gradual unfolding of autism in the first few years of life,” Piven said. “UNC has led a national network of investigators, as part of the Infant Brain Imaging Study (IBIS), in examining early behavior and early brain features that unfold as infants begin to show evidence of autism at age 2 or 3. We are a leader in this field and proud to be part of the NIH ECHO Initiative.”

The study will focus on infants who are at high risk for autism by virtue of having an older sibling with autism, as those infants have a substantially higher risk of developing autism by the time they are 2 to 3 years old.

Newschaffer, founding director of the A.J. Drexel Autism Institute, hopes to use the shed baby teeth to examine whether environmental factors play a role in further increasing that risk.

This team will study a group of 1,713 subjects called the Autism Spectrum Disorder Enriched Risk (ASD-ER) cohort. In this cohort, there are 1,281 children who are considered “high risk” because of their older sibling’s autism diagnosis, and 432 children called “low risk” because they lack a sibling with autism.

Newschaffer and his co-investigators will test lost baby teeth for levels of environmental chemicals that the children would have been exposed to while in their mother’s womb. That time is particularly important for neurodevelopment and, thus, particularly vulnerable.

Chemicals being examined in the study include organochlorine pesticides, such as DDT, and polychlorinated biphenyls, formerly used for things like insulating electrical transformers. Although banned in the 1970s, the chemicals, true to their “persistent” moniker, remain in the environment and human exposure continues. The study will also investigate phthalates, which were used to make plastics more flexible.

The researchers hope to determine whether prenatal exposure to these chemicals increases the risk of autism. Additionally, for a smaller group of participants where genetic data are already available, the researchers hope to explore whether the genetic susceptibility of a child plays any role on the effect chemical exposures have on autism risk.

Findings will be useful in determining the mechanisms underlying autism. Once such mechanisms are better understood, more effective prevention and treatment strategies can be developed.

“We’re very excited about the prospect of applying this novel approach to measuring prenatal environmental exposure in larger groups of children in ECHO,” Newschaffer said. “We’d love to integrate this with available genomics measures to, at a scale that has yet to be approached, study the interaction between genetics and environment.”

The NIH awarded $157 million for many projects under ECHO, which will investigate how exposure to environmental factors in early development — from conception through early childhood — influence the health of children and adolescents.

“Every baby should have the best opportunity to remain healthy and thrive throughout childhood,” said Francis S. Collins, MD, PhD, NIH director. “ECHO will help us better understand the factors that contribute to optimal health in children.”

Piven’s Infant Brain Imagine Study includes collaborators at UNC, Washington University, the University of Washington, and the University of Pennsylvania/Children’s Hospital of Philadelphia.